Container

Abstract

A container comprising a flexible semi-permeable composite membrane structure is described, as well as its applications. The membrane has a low molecular weight cut-off, comprises a flexible support layer thick enough to give strength to the membrane structure and having a relatively high molecular weight cut-off and, on at least one surface of the said support layer, a second layer having a relatively low molecular weight cut-off and is thin enough to allow a workable flux. Said container may be used for the preparation of rehydrated solute solutions, rehydrated blood or blood substitutes, nutritional solutions, solutions for medical purpose or of pure water.

What is claimed is:  
     
       1. Container for the preparation of rehydrated solute solutions, rehydrated blood or blood substitutes, nutritional solutions, solutions for medical purpose or of pure water comprising a flexible semi-permeable membrane and at least one water soluble solid retained therein, wherein the flexible semi-permeable membrane is a composite membrane structure having a low molecular weight cut-off, comprising a flexible support layer thick enough to give strength to the membrane structure and having a molecular weight cut-off from 1,000 to 50,000, and on at least one surface of the said support layer, a second layer having a molecular weight cut-off from 300 to 2,000 and being thin enough to allow a flux of at least 0.1 l/hr.m 2 .bar. 
     
     
       2. Container according to claim  1  wherein the wall of said container consists essentially of said flexible semi-permeable membrane. 
     
     
       3. Container according to claim  1  wherein only a portion of the wall consists of said flexible semi-permeable membrane. 
     
     
       4. Container according to claim  1  wherein the support layer of the membrane is a semi-permeable material selected from the group consisting of cellulose, regenerated cellulose, benzoylated cellulose and collagen. 
     
     
       5. Container according to claim  1  wherein the second layer of the membrane is a film of a material selected from the group consisting of cellulose derivative, synthetic organic polymer, naturally occurring polymer, modified naturally occurring polymer, and a mixture thereof. 
     
     
       6. Container according to claim  5  wherein the second layer of the membrane is a hydrophilic polyurethane film. 
     
     
       7. Container according to claim  1  wherein the second layer of the membrane is applied on at least one surface of said support layer by a process selected from solution coating, lamination, extrusion coating and in-situ polymerization. 
     
     
       8. Container according to claim  1  wherein the second layer of the membrane is applied on both surfaces of said support layer. 
     
     
       9. Process for the preparation of rehydrated solute solution of rehydrated blood or blood substitutes, of nutritional solutions, of solutions for medical purpose, or of pure water, wherein a container according to claim  1  is placed in water. 
     
     
       10. Process for the preparation of a rehydrated solute solution, of rehydrated blood or blood substitute, of a nutritional solution, of a solution for medical purpose or of pure water with a container according to claim  1  wherein said container is placed for a sufficient period of time in flowing or stagnant water.